CAM Experiment

5/24/2018 CAM Experiment

1/8

JT POOE

200625055

THEORY OF MACHINE EXPERIMENT (1-B & 2-B)

OBJECTIVE

To draw the displacement diagram base on calculated theoretical values and compare them to thedisplacement against rotational angle obtained through experiment for a flat-ended follower.

APPARATUS

Fig. 1 Front View of Apparatus

The following experiment was based on the flat-ended follower and a curve cam.

Hard springwith a spring constant of 5026 N/m and a pre-compression of 8 mm.

10-additional

disc weights

20

Lower nut

5-Recording drum

12-Return spring

13 Tappet

14-Interchangeable

pick-up (flat or

cylindrical)

16-Belt drive for the

recording drum

21nuts fixing

the cross bar

18-Lifting spindle

11-Spacing discs

22cross bar

24- knurled nut

fixing the cam

23- fixing screw


2/8

JT POOE

200625055


Fig 2- Reading Drum

Fig 2 - SPEED CONTROLLER

1. Variable speed motor,speed range between 60 and 670 rpm, power

2. Dual bearing drive shaft;

3. Protective cover for the moving parts

4. Emergency stop button;

5. Recording drum powered by the drive shaft via the belt drive at a transmission ratio o

1:1

Switch for the electric motor

Potentiometer for

speed adjustment

Speed indicator

16-Belt drive for therecording drum

6-Recording pen

5-Recording drum

covered in wax-coated

paper (indicator paper)

17-Cross-bar mechanism

driving the recording pen25-Grip nut


3/8

JT POOE

200625055


6. Recording pen is driven directly by the tappet via a crossbar

7. Probe for the recording

8. Speed sensor

9. Centrifugal mass to minimase rotationsl movement discontinuity at low speeds;

10.Additional disc weights that can be attached to the tappet upper end to increase th

moving mass

11.Spacing discs for spring pre-compression

12.Tappet guided by two maintenance free slide bearing sleeves13. Interchangeable pick-up (flat or cylindrical follower) fixed to the lower end of the tappet

14. Interchangeable cam

15.Belt drive for the recording drum

16.Cross-bar mechanism driving the recording pen.

17.Lifting spindle

18.Upper nut

19.Lower nut

20.Nuts fixing the cross bar

21.Cross bar fixing the return spring

22.Fixing screw for the interchangeable follower 14

23.Knurled nut for fixing the interchangeable cam 15

24.Grip nut

PROCEDURE

1. sRemove the knurled nut 24 and mount the circular cam 1 as shown in figure 11.

2. Attention to the front and rear view position of the cam as the cam guiding rod bore hole

situated on the rear of the cam.

3. Loosen the fixing screw 23 with the provided Allan key and insert the flat tappet followeApply a thin film of grease to the flat tappet.

4. The washer between the follower and tappet must be reinstalled in the same position durin

assembly.

5.

6. Take one sheet of wax-coated paper. Do not bend the paper or insert it with its recordin

side facing down, hold the paper by its edges with your fingertips. Handle the wax-coate

paper with care as its surface is very sensitive to scratches. Fold the narrow edge o

the paper 1012 mm back

7. From the graph obtained in the experiment, use it to draw a displacement diagram.

8. Connect the motor to the control unit.

9. Set the speed to 110 RPM.

10. Compare the calculated value with the measured results and prove that: given the sam

stroke and opening angle.

11. Using the designated set of formulae for each type of cam, draw a graph representing the

velocity against the rotation angle. Choose an increment of 100for the rotation angle.


4/8

JT POOE

200625055


Cam 2 (circulararc cam)

Base radius R = 25 mm;

Curved flank radius = 96.21 mmNose radius r = 10 mm

Maximum lift (cam stroke) h = 15 mmTotal angle of action 2 x = 140

0

Angular Velocity = 11.52 rads/s

d

R

h

r

CALCULATIONSFLANK

Formulae x= ( R)(1-Cos )

@ 0

0

@ 100

@ 200

NOSE:

Formulae Used was

@ 300

@ 400

@ 500

@ 600

@ 700


5/8

JT POOE

200625055


VELOCITY ON FLANK:@ 0

0

Formulae used

@ 100

@ 20

0

@ 300

VELOCITY ON NOSE:Formulae Used @ 30

0

@ 400

@ 500

@ 600

@ 70

0

ACCELERATION ON FLANK:Formulae used

@ 00

@ 100

@ 200

@ 30

0

ACCELERATION ON NOSE:

Formulae used @ 300

@ 40

0

@ 50

0

@ 60

0


6/8

JT POOE

200625055


@ 700

GRAPHS

0

2

4

6

8

10

12

14

16

0 10 20 30 40 50 60 70 80

Displacement(mm)

Rotational Angle(Degrees)

Displacement vs Angle

70, 00

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0 10 20 30 40 50 60 70 80

Velocity(m/s)


Velocity vs Angle


7/8

JT POOE

200625055


EXPERIMENT 2-B

OBJECTIVE

To draw the displacement diagram based on the experiment values obtained through experiment

(2-B). To compare the displacement diagrams obtained through 1-B and 2-B experiments

-6

-4

-2

0

2

4

6

8

10

12

0 10 20 30 40 50 60 70 80

Acceleration(m/s2)


Acceleration vs Angle


8/8

JT POOE

200625055


As it is seen from the graph the maximum lift of the graph occurs at 600which it is rotating a

an angular velocity of 350RPM. The maximum lift value occurred at 34.5mm to the carbon

paper then I had to divide it by 2.23 to get a maximum lift of 15.4mm.

DISCUSSION AND CONCLUSSION

I obtained the graphs by using the formulae for curve flank cam by taking into consideration theflank calculations and nose calculation. The results that I have obtained gave me similar graphs ofdisplacement, velocity and acceleration as illustrated from the theory of machines textbook. Thecalculated values they have good similarity with the values obtain during the experiment.

The comparison of the two graphs is that the smooth graph reaches 15mm at 70 0while the roughgraph reaches it in an angle of 600to the rotational. The objective of the experiment wassuccessfully carried out, the comparison of the calculated values are more identical to the valuesobtained during the experiment.

Documents

CAM Experiment